A STYLE COUPLERS - 1/4inch BASIC SIZE Aro style interchange series. A style couplers are made of heavy-duty steel; plugs are case hardened steel treated to resist rust. Push type - body engages automatically. These couplers are for use with shop air only. Specifications: All 1/4", 3/8", and 1/2" maximum inlet pressure is 300 PSI. Buna-N seals.